Networks such as the Internet and World Wide Web (web) are extremely popular to users as a source of information and entertainment. The web is used for communication between central sites (e.g., web sites) on the Internet and individual users who wish to communicate with the site. Two programs typically control the communications: a web browser that runs on the user's computer and a web server that runs on the web site's computer.
To obtain information from a web site, a web browser sends a request to a web server by transmitting a uniform resource locator (URL) address of the web site and by using a communication protocol such as Transmission Control Protocol/Internet Protocol (TCP/IP). In typical situations, such a request to the web server is in the form of a hypertext transfer protocol (HTTP) request that results in a transmission of hypertext markup language (HTML) documents (e.g., web pages) back to the web browser.
Many employers provide their employees with terminals, such as personal computers (PCs), which the employees can use to access the Internet to send/receive email and to “surf the Net.” According to a common configuration, such PCs are connected together in a company's internal network, such as a local area network (LAN), and then connected via the company's proxy server to Internet servers.
The proxy server often serves as part of the company's “firewall,” where incoming and outgoing communications can be monitored by the company's information systems. In operation, employees are generally forced to connect to the Internet via this firewall. In other words, all communications (usually in the form of packets) are passed first through the proxy server, and then out to the destination web site. Similarly, content requested from the Internet, such as HTML pages, are first sent to the proxy server, and then forwarded to the employee's terminal for display by a web browser.
Because of this standard network architecture, individual terminals (e.g., users or employees) are vulnerable to the monitoring of: a) content uploaded by the user to a web site, such as Internet email messages that the user writes and sends; b) content downloaded from a web site, such as HTML pages viewed on the web site or Internet email messages that the user receives and reads; and c) the Internet Protocol (IP) or URL addresses of servers to which the user sends/receives packets.
There are similar privacy and security issues involved with network architectures other than the corporate network described above. For example, users accessing the Internet from terminals in their homes sometimes have their packets routed through an Internet Service Provider (ISP) and/or along a system having a ring or loop configuration, such as a cable modem system. In such situations, hackers or other parties have the opportunity to monitor individual users' communication at the ISP or at other locations, and thus can obtain information that the users wish to keep confidential, such as URLs of visited web sites, IP addresses of servers used, content (e.g., HTML pages or email) sent/received by the user, etc.
Additional mechanisms are implemented by Internet-based systems that further jeopardize the freedom of users to communicate privately and securely with the Internet. For instance, companies that control employees' Internet usage sometimes implement firewall blocking or filtering to prevent access to particular web sites. Also, visited web sites often record IP addresses of clients (e.g., users) and collect other data to help identify clients during a profiling process. Further, web servers typically transmit “cookies” for storage in users' terminals. Cookies are electronic files sent by the web server to the web browser to help identify the user and to prepare customized web pages when the user returns to the web site. In typical situations, web pages and histories of URLs accessed (e.g., a web browser history file) are stored at the user's terminals, thereby further compromising the privacy of the user.
In short, there is a need to improve private and secure communications over networks such as the Internet.